kz750 ltd h2 1981 - will crank wont start fully?

hi tek!

thank you for your advice!

i understand what you mean about the rig.
are the carbs the correct way up or upside down please?

so the carbs are bolted to the cross, fuel
fed by a temp fuel tank. then i get lost.
i've never done this before, sorry dudey!

the carbs are the correct way up or upside
down?

many thanks tek!

regards

Angel

"how many tubes should there be in the petcock tank fuel filter please?
mine has a central one, that goes halfway up the filter. it fits into a recess/hole in the petcock.
yet my petcock has room for another pipe, by the side of the main petcock tube."

Normally the petcock has 2 openings inside the fuel tank. One has a tube sticking up from it; maybe an inch or so long. The other has no tube. The one with the tube is the orifice that normally feeds fuel to the carbs. The idea is that when fuel in the tank runs low it will drop below the level of the top of the tube and the bike will appear to run out of gas. At that point, when you switch the petcock handle to "Reserve", fuel is fed to the carbs through the second orifice (the one with no tube). The opening to this orifice is nearly level with the bottom of the fuel tank (because it has no tube). So that 1 inch tube represents the level of fuel that is left in the tank when you switch to reserve. Ed

hi patton

re: setting correct fuel levels

many thanks for the clear tube method.
i'm slightly confused about setting up the
rig!...

1) make a wood cross shaped frame
to hold the set of carbs. are the carbs put
upside down, with the nipple bowls on the top?
connect up overflow/drain tubes to nipples.

2) connect up a temp fuel tank to feed carbs.

3) unscrew each bowl in turn, turn screw to
fill each overflow tube to prove fuel level?
adjust float levels as and if necessary?
repeat 2,3, 4 nipple bowls.

is my understanding correct?

please read my posting with a photo today.

many thanks

Angel

what stars you all are.

many thanks!... i only put one tube in the centre,
the same length as the workshop manual.
the manual assume common knowledge.

i would love to see a photo of how
to set up a wooden cross rig, to
bolt on your carbs, which way though?
correct way up or upside down?

all nipple bowls off one at a time or all together?

i'm confused about the correct way to
set the above rig up? ..... damsel in distress guru's!

Take a look at Joe's video in this link (skip down just a little past the picture of the clear plastic bowl):

kzrider.com/forum/3-carburetor/500682-clear-float-bowls#503278

steelhorseangel wrote: ...the internal
tank filter, connected to the petcock.
inside the tank filter, there is a tube inside the filter.
this central tube fits in the base of petcock. this
is one tube, next to this tube is another hole.
does a second tube (smaller) fit into this
second hole?....

The second hole doesn't have a tube, as the second hole accepts fuel until the tank runs dry.

But the second hole might have its own separate filter.

The petcock's so-called "filters" are just screens which help prevent some of the larger grit from passing on to the carbs.

This is why aftermarket in-line fuel filters are necessary.




Good Fortune!

q)

when i unscrew the nipple bowl drain screws
fuel only drains out of two tubes only?
on unscrewing the other two drain screws,
the fuel comes out of the screw holes and not
the nipples?

blockage somewhere?

NIPPLE BOWLS
on draining the nipple bowls (for carb inspection) by using clear drain tubes, connected to the nipples. i unscrewed each screw in turn. i expected the fuel to come out of the nipples, yet in two cases the fuel came out of the screw holes? two were like this, no nipples drainage!.

If fuel fails to discharge through the drain nipples from bottom of the float bowl, would suspect that the overflow circuit is clogged.

As to performing the clear tube test with carbs on the work bench, I simply hold or prop the carbs upright and level while performing the clear tube test, and don't bother with any separate rigging or clamping the carbs to a board, etc. Chalk it up to laziness. :lol:

Good Fortune!

thank you patton!

i laughed out loud!

how do i unblock the overflow system please?

such a big learning curve, nearly there!...

kind regards mr guru

Angel

when i unscrew the nipple bowl drain screws
fuel only drains out of two tubes only?
on unscrewing the other two drain screws,
the fuel comes out of the screw holes and not
the nipples?
blockage somewhere?

Please wear eye protection while spraying carb cleaner, because it always backfires.

Am thinking (not positive) that these are Keihin CV carbs with a dual function drain screw.

With the screw tightened, the overflow circuit is supposed to function.
This means if excess incoming fuel is getting past the float valve (for whatever reason) and rising up too high inside the float bowl, the rising fuel is supposed to only get as high as top of the overflow tube.

Upon reaching height of the overflow tube, the excess fuel is supposed to then escape down through the overflow tube and exit through the nipple.

With the drain screw loosened, the float bowl is allowed to drain completely.

Must be careful when attempting to clear the overflow passageway so as not to break off, crack, crimp or otherwise damage the rather thin fragile overflow tube.

The following could be done with the float bowl removed and in hand.

With the drain screw tightened (whereby overflow circuit is operational), could try to clear the overflow passageway by blasting through it, by spraying carb spray into the nipple, and hoping to see the spray exit from top of the overflow tube.

Could also try spray blasting the opposite direction, starting at tip of the overflow tube, and hoping to see the spray exit from the overflow nipple.

Could also remove the drain screw, and try spraying into the drain screw hole while blocking the nipple hole with a finger, and hoping to see the spray exit from top of the overflow tube.

Could also remove the drain screw, and try spraying into the drain screw hole while gently blocking top of the overflow tube with a finger, and hoping to see the spray exit from the overflow nipple.

Also, the drain screw is supposed to have an o'ring, which I believe may prevent or minimize fuel leakage when the screw is loosened.

Good Fortune!

a big thank you!

i've some eye protection, for the overflow
job tomorrow. i will make sure that i don't
spray any rubber etc. i greatly appreciate
your help and advice!

it's better to do a complete job from start
to finish. i like this situation, a conundrum
that is a learning curve as well.
the last owner made a message of one
of the carbs internal fittings, it was stuck
and partly broken. i bought an easy out, knew
it would come in handy. bought two spare
keihin carb shells, my doner supplies!

thank you!

Angel

Yeah, the carbs are right side up (normal/onbike) position. As in Pattons pictures...

Bowls on. Perform clear tube test on one bowl/carb at a time - setting it correctly, then move on to the next. With a rig like i described, it shouldnt take more than 30 minutes to set all fuel heights correctly and move on to the next thing. (we dont have alot of time in the shop to screw around) :laugh:
If you have to set the floats very high (pushing float needle spring up hard) to get the fuel level correct - use some metal/brass polish and some cotton swabs to polish the float valve seat to shiney like new state.

If you have metal float needles, good idea to put them in a drill and spin polish them too.
If rubber, make sure they are clean/no cracks, and shouldnt have any severe indentations.

Good luck!